1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
|
/* ISC license. */
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <skalibs/posixplz.h>
#include <skalibs/uint16.h>
#include <skalibs/uint32.h>
#include <skalibs/types.h>
#include <skalibs/error.h>
#include <skalibs/strerr.h>
#include <skalibs/sgetopt.h>
#include <skalibs/allreadwrite.h>
#include <skalibs/tai.h>
#include <skalibs/socket.h>
#include <skalibs/ip46.h>
#include <skalibs/cdb.h>
#include <skalibs/sig.h>
#include <skalibs/iopause.h>
#include <skalibs/selfpipe.h>
#include <s6/accessrules.h>
#include <shibari/common.h>
#include <shibari/server.h>
#define USAGE "shibari-server-udp [ -U ] [ -v verbosity ] [ -d notif ] [ -f cdbfile ] [ -w wtimeout ] [ -i rulesdir | -x rulesfile ] [ -p port ] ip"
#define dieusage() strerr_dieusage(100, USAGE)
#define VAR "LOC"
static char const *tdbfile = "data.cdb" ;
static cdb tdb = CDB_ZERO ;
static cdb rules = CDB_ZERO ;
static char const *rulesfile = 0 ;
static unsigned int rulestype = 0 ;
static int cont = 1 ;
static uint32_t verbosity = 1 ;
static inline void reload_cdbs (void)
{
cdb newtdb = CDB_ZERO ;
if (!cdb_init(&newtdb, tdbfile))
{
if (verbosity) strerr_warnwu2sys("reopen DNS data file ", tdbfile) ;
}
else
{
cdb_free(&tdb) ;
tdb = newtdb ;
}
if (rulestype == 2)
{
cdb newrules = CDB_ZERO ;
if (!cdb_init(&newrules, rulesfile))
{
if (verbosity) strerr_warnwu2sys("reopen access rules file ", rulesfile) ;
}
else
{
cdb_free(&rules) ;
rules = newrules ;
}
}
}
static int check_rules (ip46 const *remoteip, s6_accessrules_params_t *params, char const **loc)
{
s6_accessrules_result_t r ;
params->env.len = 0 ;
params->exec.len = 0 ;
r = rulestype == 2 ?
s6_accessrules_ip46_cdb(remoteip, &rules, params) :
s6_accessrules_ip46_fs(remoteip, rulesfile, params) ;
if (r != S6_ACCESSRULES_ALLOW) return 0 ;
if (params->env.len)
{
char const *p ;
if (params->env.s[params->env.len - 1])
{
if (verbosity)
{
char fmt[IP46_FMT] ;
fmt[ip46_fmt(fmt, remoteip)] = 0 ;
strerr_warnw6x("invalid environment parameters in rules ", rulestype == 2 ? "cdb " : "directory ", rulesfile, " for ip ", fmt, " - denying connection") ;
}
return 0 ;
}
p = memmem(params->env.s, params->env.len - 1, VAR "=", sizeof(VAR)) ;
if (p && (p == params->env.s || !p[-1])) *loc = p + sizeof(VAR) ;
}
return 1 ;
}
static inline void handle_signals (void)
{
for (;;) switch (selfpipe_read())
{
case -1 : strerr_diefu1sys(111, "read selfpipe") ;
case 0 : return ;
case SIGTERM : cont = 0 ; break ;
case SIGHUP : reload_cdbs() ; break ;
default : break ;
}
}
int main (int argc, char const *const *argv)
{
iopause_fd x[2] = { { .events = IOPAUSE_READ }, { .events = IOPAUSE_READ } } ;
tain wtto = TAIN_INFINITE_RELATIVE ;
s6_accessrules_params_t params = S6_ACCESSRULES_PARAMS_ZERO ;
unsigned int notif = 0 ;
uid_t uid = 0 ;
gid_t gid = 0 ;
char buf[512] ;
shibari_packet pkt = SHIBARI_PACKET_INIT(buf, 512, 0) ;
uint16_t localport = 53 ;
ip46 localip ;
PROG = "shibari-server-udp" ;
{
unsigned int wtimeout = 0 ;
int flagdrop = 0 ;
subgetopt l = SUBGETOPT_ZERO ;
for (;;)
{
int opt = subgetopt_r(argc, argv, "Uv:d:f:w:i:x:p:", &l) ;
if (opt == -1) break ;
switch (opt)
{
case 'U' : flagdrop = 1 ; break ;
case 'v' : if (!uint320_scan(l.arg, &verbosity)) dieusage() ; break ;
case 'd' : if (!uint0_scan(l.arg, ¬if)) dieusage() ; break ;
case 'f' : tdbfile = l.arg ; break ;
case 'w' : if (!uint0_scan(l.arg, &wtimeout)) dieusage() ; break ;
case 'i' : rulesfile = l.arg ; rulestype = 1 ; break ;
case 'x' : rulesfile = l.arg ; rulestype = 2 ; break ;
case 'p' : if (!uint160_scan(l.arg, &localport)) dieusage() ; break ;
default : strerr_dieusage(10, USAGE) ;
}
}
argc -= l.ind ; argv += l.ind ;
if (!argc) dieusage() ;
if (!ip46_scan(argv[0], &localip)) dieusage() ;
if (flagdrop)
{
char const *x = getenv("UID") ;
if (!x) strerr_dienotset(100, "UID") ;
if (!uid0_scan(x, &uid)) strerr_dieinvalid(100, "UID") ;
x = getenv("GID") ;
if (!x) strerr_dienotset(100, "GID") ;
if (!uid0_scan(x, &gid)) strerr_dieinvalid(100, "GID") ;
}
if (wtimeout) tain_from_millisecs(&wtto, wtimeout) ;
}
if (notif)
{
if (notif < 3) strerr_dief1x(100, "notification fd cannot be 0, 1 or 2") ;
if (fcntl(notif, F_GETFD) == -1) strerr_diefu1sys(111, "check notification fd") ;
}
close(0) ;
close(1) ;
x[0].fd = selfpipe_init() ;
if (x[0].fd == -1) strerr_diefu1sys(111, "create selfpipe") ;
if (!sig_altignore(SIGPIPE)) strerr_diefu1sys(111, "ignore SIGPIPE") ;
{
sigset_t set ;
sigemptyset(&set) ;
sigaddset(&set, SIGHUP) ;
sigaddset(&set, SIGTERM) ;
if (!selfpipe_trapset(&set)) strerr_diefu1sys(111, "trap signals") ;
}
if (!cdb_init(&tdb, tdbfile)) strerr_diefu2sys(111, "open cdb file ", tdbfile) ;
if (rulestype == 2 && !cdb_init(&rules, rulesfile)) strerr_diefu2sys(111, "open rules file ", rulesfile) ;
x[1].fd = socket_udp46_nb(ip46_is6(&localip)) ;
if (x[1].fd == -1) strerr_diefu1sys(111, "create socket") ;
if (socket_bind46_reuse(x[1].fd, &localip, localport) == -1) strerr_diefu1sys(111, "bind socket") ;
if (gid && setgid(gid) == -1) strerr_diefu1sys(111, "setgid") ;
if (uid && setuid(uid) == -1) strerr_diefu1sys(111, "setuid") ;
if (!tain_now_set_stopwatch_g()) strerr_diefu1sys(111, "initialize clock") ;
shibari_log_start(verbosity, &localip, localport) ;
if (notif)
{
write(notif, "\n", 1) ;
close(notif) ;
}
while (cont)
{
tain wstamp = TAIN_INFINITE ;
char const *loc = 0 ;
s6dns_message_header_t hdr ;
s6dns_message_counts_t counts ;
s6dns_domain_t name ;
unsigned int rcode ;
ssize_t r ;
uint16_t qtype ;
uint16_t remoteport ;
ip46 remoteip ;
if (iopause_g(x, 2, &wstamp) == -1) strerr_diefu1sys(111, "iopause") ;
if (x[0].revents & IOPAUSE_EXCEPT) strerr_dief1x(111, "trouble with selfpipe") ;
if (x[0].revents & IOPAUSE_READ) { handle_signals() ; continue ; }
r = sanitize_read(socket_recv46(x[1].fd, buf, 512, &remoteip, &remoteport, ip46_is6(&localip))) ;
if (!r) continue ;
if (r == -1) strerr_diefu1sys(111, "recv from socket") ;
if (rulestype && !check_rules(&remoteip, ¶ms, &loc)) continue ;
if (!s6dns_message_parse_init(&hdr, &counts, buf, r, &rcode)) continue ;
if (hdr.opcode) { rcode = 4 ; goto answer ; }
if (!s6dns_message_parse_question(&counts, &name, &qtype, buf, r, &rcode) || !s6dns_domain_encode(&name))
{
rcode = errno == ENOTSUP ? 4 : 1 ;
goto answer ;
}
shibari_log_queryplus(verbosity, &name, qtype, &remoteip, remoteport) ;
tain_wallclock_read(&wstamp) ;
rcode = shibari_packet_tdb_answer_query(&pkt, &tdb, &hdr, &name, qtype, loc, &wstamp) ;
answer:
if (rcode && rcode != 3)
{
shibari_packet_begin(&pkt, hdr.id, &name, qtype) ;
pkt.hdr.rcode = rcode ;
shibari_packet_end(&pkt) ;
}
shibari_log_answer(verbosity, &pkt.hdr, pkt.pos) ;
tain_add_g(&wstamp, &wtto) ;
if (socket_sendnb46_g(x[1].fd, buf, pkt.pos, &remoteip, remoteport, &wstamp) < pkt.pos && verbosity)
strerr_warnwu1sys("send answer") ;
}
shibari_log_exit(verbosity, 0) ;
return 0 ;
}
|
